Leukemia is a set of blood cancer characterized by the uncontrolled growth of developing white blood cells. The accumulation of cancerous cells interferes with the body's production of healthy blood cells therefore impairing immune response to infection. Worldwide, an estimated 257,000 new cases of leukemia are diagnosed each year, with approximately 195,000 deaths annually. According to the American Cancer Society, 30,800 new cases of all types of leukemia were reported in the US in 2003. Leukemia is the number one cause of deaths from cancer in children and young adults under age 20. One of the most important laboratory features used to categorize leukemia patients is the specific chromosomal translocations within the leukemia blasts, which are used to choose the therapeutic options that are likely to provide the best outcomes. Fusion proteins formed by the translocations are thought to contribute to the development and progression of leukemia and are thus therapeutic targets as well as diagnostic markers. New therapeutic approaches are likely to further increase the importance of identifying specific leukemia-associated translocations in order to determine the most effective course of treatment. Liquid bead arrays with flow cytometry detection are particularly suited to the requirements of the diagnostic laboratory and will be the basis for our multiplex detection assay using the Luminex xMAP technology platform. This format has been generally applied to clinical analytes, including serologic, genetic, and infectious disease targets. Phase I funding for this project supported the successful development of a rapid single-tube assay for simultaneous detection of leukemia-associated chromosome translocations using fusion transcripts as markers (21 fusion transcript markers). The phase I study also showed the feasibility of a comprehensive control system for use in clinical implementation of the assay. As a result we have launched a kit (for Research Use Only, RUO) for rapid detection of 12 fusion transcript markers from most common leukemia-associated translocations under the trade name Signature LTx Leukemia Translocation Panel. The ultimate goal of proposed phase II project is to adapt and expand this assay into a robust, high-throughput clinic diagnostic kit for rapid risk-stratification in leukemia. Specific Aims of Phase II are: 1. Expand the assay to include additional clinically relevant markers. 2. Develop a comprehensive assay control system for clinical test of this assay. 3. Clinical evaluation of our assay system for rapid leukemia subtyping (risk stratification). The overall goal of this proposal is to develop an assay (Signature LTx) for subtyping and risk-stratification of leukemia. This liquid bead array format of this assay will provide efficiency and cost benefits to diagnostic laboratories and provide crucial information to physicians and patients for use in making treatment decisions. [unreadable] [unreadable] [unreadable]